Method and apparatus for determining exertion levels interested in this invention are disclosed, for example, in International Publication No. WO96/20640. According to the disclosure, heartbeat of a person engaged in training is monitored. From an electrocardiographic signal obtained, a QRS complex waveform, for example, is measured to calculate the heartbeat rate. Based on a power of a spectrum derived from the heartbeat rate, an exertion level of the exercising person is determined.
Further, conventional method and apparatus for measuring muscular endurance of a person engaged in exercise are disclosed, for example, in Japanese Patent Publication No. 7-38885. According to the disclosure, a load of an exercising person is calculated from the product of a heartbeat rate and a blood pressure under vasoconstriction, and from the result, the muscular endurance is calculated.
The load of a person engaged in training or exercise has conventionally been measured as described above. Such measurement has also made it possible to estimate the load of an exercising person.
Conventionally, exercise machines such as a bicycle ergometer and others have been commercially available for health maintenance and enhancement. In some of such exercise machines, a person inputs his/her age, sex and the like, and an exercise program is arranged according to such information based on statistically predetermined exertion intensity. For evaluation of a physical strength level, some machines have adapted a method of estimating the maximum oxygen intake based on a change of pulsation or the like corresponding to a change of exertion load.
There is a factor for decision of safe and effective exercise; i.e., an anaerobic threshold (hereinafter, also referred to as “AT”). This threshold value of exertion intensity shows a maximum exertion level at which exercise can be done without an abrupt increase of lactic acid in the blood. The AT is conventionally determined employing an invasive method by taking a blood sample to examine the lactic acid level, or in a restraining manner by measuring changes of oxygen and carbondioxide partial pressures in exhalation by breathing gas analysis.
Further, for evaluation of physical strength, there are conventionally known methods of estimating maximum oxygen intake, maximum exertion intensity, maximum heartbeat rate and others based on a change of pulsation or the like with respect to the exertion load.
Such conventional exercise machines and apparatuses for determining exertion levels, however, have posed the following problems:
{circle around (1)} The data obtained from the apparatus and method for determining the exertion level has been used only physiologically to determine the exertion level in training or exercise; the data has not been utilized effectively.
{circle around (2)} Setting of exertion intensity does not conform to working capacity of each person; a sought-after effect cannot be obtained sufficiently from the exercise.
{circle around (3)} Although the AT is considered most appropriate as the exertion intensity in conformity with the working capacity of the individual, measurement of the AT is restraining and requires a special apparatus such as a breathing gas analyzer; such a measuring apparatus cannot practically be mounted on an exercise machine.
{circle around (4)} The AT, which represents aerobic working capacity important for decision of physical strength, cannot be determined by or displayed on the exercise machine due to the reason stated in {circle around (3)} above.
The present invention is directed to solve the above-described problems, and its object is to provide an exercise machine which allows an exertion level to be readily and accurately found so that the value can be used for effective training.
Another object of the present invention is to provide an exercise machine which allows an anaerobic threshold to be readily and accurately found so that the value can be used for effective training.
Yet another object of the present invention is to provide an exercise machine and a physical strength evaluating method which allow physical strength and exertion levels to be readily found at the same time, allow a user to understand his/her own working capacity in more detail to do appropriate exercise, and allow the physical strength and exertion levels to be evaluated with high precision in a time period as short as possible.
A still further object of the present invention is to provide a pulse rate meter which allows an exertion level to be readily and accurately found.